Finish implementing alpha-version of the C-backend.

This produces valid C code in a header file and also provides an INTF
macro which makes it much less obtuse to call the various functions to
set and unset bitfields.

1 files changed, 46 insertions, 26 deletions

diff --git a/src/Language/Fiddle/Compiler/Backend/Internal/FormattedWriter.hs b/src/Language/Fiddle/Compiler/Backend/Internal/FormattedWriter.hs
index bde9ebe..000dfa4 100644
--- a/src/Language/Fiddle/Compiler/Backend/Internal/FormattedWriter.hs
+++ b/src/Language/Fiddle/Compiler/Backend/Internal/FormattedWriter.hs
@@ -3,21 +3,30 @@
 {-# LANGUAGE OverloadedStrings #-}
 
 -- | This module provides the 'FormattedWriter' monad, which extends a basic
--- "Writer" over 'Text' by allowing formatting features like indentation, line 
--- breaks, and ensuring the output is well-structured for readability. 
--- 
+-- "Writer" over 'Text' by allowing formatting features like indentation, line
+-- breaks, and ensuring the output is well-structured for readability.
+--
 -- The 'FormattedWriter' is useful for generating pretty-printed output, such as
 -- source code generation, where indentation and newline management are essential.
 module Language.Fiddle.Compiler.Backend.Internal.FormattedWriter
   ( -- * Types
-    FormattedWriter,       -- | The main writer monad with formatting features.
+    FormattedWriter,
+    -- | The main writer monad with formatting features.
     -- * Core Operations
-    ensureNL,              -- | Ensures that there is a newline at the end of the current line.
-    flush,                 -- | Flushes any pending text (writes the pending line).
-    incIndent,             -- | Increases the indentation level.
-    decIndent,             -- | Decreases the indentation level.
-    indented,              -- | Performs an action with increased indentation.
-    execFormattedWriter,   -- | Runs the 'FormattedWriter' and produces the final formatted 'Text'.
+    ensureNL,
+    -- | Ensures that there is a newline at the end of the current line.
+    flush,
+    -- | Flushes any pending text (writes the pending line).
+    incIndent,
+    -- | Increases the indentation level.
+    decIndent,
+    -- | Decreases the indentation level.
+    indented,
+    -- | Performs an action with increased indentation.
+    execFormattedWriter,
+    -- | Runs the 'FormattedWriter' and produces the final formatted 'Text'.
+    cMacroModeStart,
+    cMacroModeStop,
   )
 where
 
@@ -27,12 +36,15 @@ import Data.Text (Text)
 import qualified Data.Text as Text
 
 -- | Internal state for the 'FormattedWriter' monad.
--- 
+--
 -- * 'indentLevel': The current level of indentation.
 -- * 'pendingLine': The current line that is being built but not yet written.
 data Fmt = Fmt
-  { indentLevel :: Int,    -- ^ Current indentation level.
-    pendingLine :: Text    -- ^ Text that has been added but not yet written to the output.
+  { -- | Current indentation level.
+    indentLevel :: Int,
+    linePost :: Text,
+    -- | Text that has been added but not yet written to the output.
+    pendingLine :: Text
   }
 
 -- | The 'FormattedWriter' is a monad that provides functionality for writing
@@ -52,12 +64,14 @@ instance MonadWriter Text FormattedWriter where
     -- For each line, write the indent, the pending line, and then the line itself.
     forM_ (Prelude.init lines) $ \line -> do
       pending <- gets pendingLine
-      modify $ \s -> s {pendingLine = ""}  -- Reset pending line
-      tell indent  -- Add indentation
+      lp <- gets linePost
+      modify $ \s -> s {pendingLine = ""} -- Reset pending line
+      tell indent -- Add indentation
       tell pending -- Write any pending text
-      tell line    -- Write the actual line
-      tell "\n"    -- Add a newline after the line
-    -- The last fragment is kept as the new pending line, to be written later.
+      tell line -- Write the actual line
+      tell lp
+      tell "\n" -- Add a newline after the line
+      -- The last fragment is kept as the new pending line, to be written later.
     modify $ \s -> s {pendingLine = pendingLine s <> Prelude.last lines}
 
   -- Allow listening to the written text within the 'FormattedWriter' context.
@@ -85,29 +99,35 @@ flush :: FormattedWriter ()
 flush = do
   p <- gets pendingLine
   modify $ \s -> s {pendingLine = ""}
-  tell p
+  lp <- gets linePost
+  tell (p <> lp)
 
 -- | Increases the indentation level by one. This will affect all subsequent
 -- lines written within the 'FormattedWriter' monad.
 incIndent :: FormattedWriter ()
-incIndent = modify (\(Fmt id p) -> Fmt (id + 1) p)
+incIndent = modify (\f -> f {indentLevel = indentLevel f + 1})
 
 -- | Decreases the indentation level by one. This will affect all subsequent
 -- lines written within the 'FormattedWriter' monad.
 decIndent :: FormattedWriter ()
-decIndent = modify (\(Fmt id p) -> Fmt (id - 1) p)
+decIndent = modify (\f -> f {indentLevel = indentLevel f - 1})
+
+cMacroModeStart :: FormattedWriter ()
+cMacroModeStart = modify (\f -> f { linePost = " \\" })
+
+cMacroModeStop :: FormattedWriter ()
+cMacroModeStop = modify (\f -> f { linePost = "" })
 
 -- | Runs the given 'FormattedWriter' action with an additional indentation level.
 -- Once the action completes, the indentation level is decreased.
 indented :: FormattedWriter () -> FormattedWriter ()
 indented fn = do
-  incIndent  -- Increase indentation level
-  fn         -- Run the action with the increased indentation
-  decIndent  -- Restore the original indentation level
+  incIndent -- Increase indentation level
+  fn -- Run the action with the increased indentation
+  decIndent -- Restore the original indentation level
 
 -- | Runs a 'FormattedWriter' and returns the final formatted 'Text' output.
 -- It ensures that any pending lines are flushed before returning the result.
 execFormattedWriter :: FormattedWriter a -> Text
 execFormattedWriter ((>> flush) -> FormattedWriter rws) =
-  snd $ execRWS rws () (Fmt 0 "")  -- Execute the RWS monad, starting with no indentation and no pending line.
-
+  snd $ execRWS rws () (Fmt 0 "" "") -- Execute the RWS monad, starting with no indentation and no pending line.